IRVING, TEXAS (AP) - Not even cancer surgery can keep former NFL coach Buddy Ryan from being in the stands when his twin sons coach against each other Sunday night in the prime-time opener between the Dallas Cowboys and New York Jets.

Cowboys defensive coordinator Rob Ryan said Monday his dad was diagnosed last week with a form of cancer “in his gland that’s right through his neck.” Brother Rex, the Jets coach, said through a team spokesman that it was the parotid gland, the largest of the salivary glands.

Having already beaten melanoma in 1968 and ‘80, and another form of the disease earlier this year, the 80-year-old Ryan said this was “less serious” except that “whenever you go under anesthesia, you never know what’s going to happen.” So he told doctors to postpone the operation until he returns from the Meadowlands to see Rob and the Cowboys play against Rex and the Jets. He said he’ll fly to New York on Friday and will return to his home in Kentucky on Monday.

“They said to go ahead and go,” Ryan said during a telephone interview. “I’ve got to be able to do something” while waiting for the operation.

“That’s just the way he is,” he said. “This is a big thing for him, a big thing for the Ryans. He’s just about the only guy that’s beaten cancer about every time. He’s been through it about four or five times. I’m sure the prognosis is great for him because he always wins.”

He said his father’s illness will be more motivation than distraction.

“All he taught us is `Do the job,’” Rob said. “That’s the way he is, so it’s not that difficult. Obviously, (we’re) praying a lot for him and things have to go well because that’s what it is. But he raised us to do the job. Whatever we do, we’re going to be the best at it _ and that’s what we are.”

From Jets camp, Rex added: “It’s going to be great having him here. I know this is huge for him. He’s looked forward to it for a long time.”

Buddy Ryan was as outspoken and boisterous as his boys are, a persona he could back up with his team’s success on the field.

He was defensive coordinator of two renowned Super Bowl champions, the Joe Namath-led Jets who pulled off the huge upset in 1969, and the 1985 Bears who ran his 46 defense to perfection. He is also known for throwing a punch at the offensive coordinator while he was running the Oilers’ defense. Ryan also had entertaining stints as the head coach of the Eagles and the Cardinals.

Both sons were on their dad’s staff with the Cardinals in 1994 and ‘95. They’ve since made a name for themselves, with Rex leading the Jets to the AFC championship game the last two years, and Rob winning two Super Bowls as an assistant coach for the Patriots’ Bill Belichick. This is Rob’s first season in Dallas after working as defensive coordinator of the Browns and Raiders the last four years.

The brothers have squared off before, and every time is special for the Ryan family, especially the patriarch.

“This game’s important to him,” Rob said. “He wants to see these two rams bat heads.”